I. Field of the Invention
The present disclosure relates to power reduction in wireless communication devices. In particular, the present disclosure relates to power reduction in multiple receiver wireless communication devices.
II. Related Art
Portable wireless communication devices typically are designed to operate in widely varying operating conditions using battery power. The change in operating conditions may be due to changes in the external environment in which the wireless communication system operates. For example, the operating environment may range from a climate controlled indoor environment to high and low temperature extremes in an outdoor environment.
A wireless communication device typically experiences a wide range of electrical operating conditions. For example, the wireless communication device may experience wide fluctuations in channel conditions as a result of physical movement or re-orientation of the wireless communication device. The wireless communication device may experience fast channel fades across some or all of the operating frequencies due to destructive signal combination from multiple signal paths. Additionally, the wireless communication devices may experience slow channel fades that may occur as a result of changes in geographic location. For example, the received signal strength at a wireless communication device typically decreases as the distance to the source increases. Moreover, changes in the terrain surrounding the wireless communication device that occur as a result of movement can contribute to or remove occlusions that attenuate signals directed to the wireless communication device.
A wireless communication device can implement multiple receivers, for example, arranged as diversity receivers to improve performance of the wireless communication device over the wide range of operating conditions. The use of diversity receivers can improve the received signal quality where one or more of the receivers receive a weak signal. For example, where the antennas for the diversity receivers have spatial diversity, one antenna may receive a signal that experiences a strong signal fade while the other antenna can receive a signal that does not experience a substantial fade.
Although the use of diversity receivers may improve signal quality across the range of operating conditions, the multiple receivers consume greater power than is typically consumed by a single receiver path. Power consumption is typically of great concern in a portable device. The power consumed by the wireless communication device directly relates to its battery life. Users of wireless communication devices typically desire to extend the operating time between successive battery charges. Therefore, the desire to operate across a wide range of operating conditions, including marginal operating conditions, operates in contrast to the desire to conserve battery power during operating conditions.